Crashing on iOS 14.6+ - Symbol not found

[tylerjames]

Strangely getting a crash now when run on iOS 14.6+ but not iOS 15. App crashes right at startup with this message. Strangely had this in the app for a while and it only started causing a problem recently. Built on an M1 Pro. Not sure if that makes a difference

dyld: Symbol not found: _$sSo22NSManagedObjectContextC8CoreDataE5fetchySayypGSo14NSFetchRequestCySo0gH6Result_pGKF Referenced from: /private/var/containers/Bundle/Application/8201E96C-E94C-4495-9983-AFDB219DB2E7/MyApp.app/Frameworks/SweeterSwift.framework/SweeterSwift Expected in: /usr/lib/swift/libswiftCoreData.dylib

dyld: launch, loading dependent libraries DYLD_LIBRARY_PATH=/usr/lib/system/introspection DYLD_INSERT_LIBRARIES=/Developer/usr/lib/libBacktraceRecording.dylib:/Developer/usr/lib/libMainThreadChecker.dylib:/Developer/Library/PrivateFrameworks/DTDDISupport.framework/libViewDebuggerSupport.dylib

[yonat]

Wow, this is a tough one! Would you create a minimal project that reproduces this problem so I can check it? (See https://ootips.org/yonat/repex/)

[tylerjames]

If I can get to around it.

It comes from the SweeterSwift library. But Multislider only uses extensions from UIView+Sweeter. It's the NSManagedContext one that seems to be causing a problem.

It's very strange because I've had this library in use for months and I'm sure it's run on iOS 14 before. I recently got an M1 Pro so I don't know if it's just building it differently. There's no compiler error associated with it. It's just a runtime crash due to the code merely existing (it's never called by Multislider)

I made a fork that just removes the SweeterSwift dependency and copies over the UIView+SweeterSwift extension and that was enough to get it working.

[tylerjames]

Okay I found the issue. In your NSManagedObjectContext.printAllObjects() function on this line: guard let objects = try? fetch(NSFetchRequest(entityName: entityName)) else { continue }

Change it to this: guard let objects = try? fetch(NSFetchRequest<NSFetchRequestResult>(entityName: entityName)) else { continue }

I don't know why it causes a crash on iOS 14 just by existing in the first form but adding the generic fixes it.

[yonat]

Thanks! I wasn't able to reproduce the crash, but the change you suggest doesn't cause any problems so I add it to SweeterSwift 1.2.1 .